Tuesday, June 5, 2012

Stack-to-Pot Ratio, Part 1: What is SPR?

Want to make your post-flop decisions easier in cash games? Enter SPR, or Stack-to-Pot Ratio.

Ed Miller, et al, coined this term in "Professional No Limit Hold’em: Volume I," which is a book I highly recommend. Lots of useful stuff there for the strong intermediate player to take in. Among the good stuff is the concept of SPR:

SPR = Size of the effective stack divided by the pot size on the flop.

For example, let's say you raise to $8 in a $1/2 NL cash game, where everyone started with $200 stacks. Only one field player calls, and both blinds fold. There is no rake. What's the SPR?

The pot size is: $8 + $8 + $1 + $2 = $19.

The effective stack size is: $200 - $8 = $192.

The SPR is therefore: $192 / $19 = 10.1

When calculating SPR, you must use the effective stack size. If you had $200 to start this hand example, but your opponent only had $100, the effective stack size after the flop would have been $100 - $8 = $92, and therefore the SPR would have been $92 / $19 = 4.8.

Also note that SPR is calculated only on the flop, prior to any flop betting. It is not used on the turn or river.

In the next installment of this topic, I will show how SPR is essentially a measure of the risk and reward of a hand. More importantly, I'll start to show how it's a powerful tool we can use to help estimate our pot commitment level in a hand, and how it can therefore be used to help us plan to get stacks into the middle early in a hand. In other words, we'll use SPR to try to create situations where we (and/or our opponents) become committed (or not). Stay tuned.

All-in for now...

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